Biosorption of cadmium to mycelial pellets of wood-rotting fungi

Summary Fungal pellets of wood-rotting fungi (diameters ranged from 0.2 to 2 cm) were obtained by submerged cultivation on nutrient rich medium. Biosorption of cadmium (initial concentration, 10 mM) in batch system was followed by HPLC. Of 20 fungal strains tested, high abilities to accumulate cadmium were found in Fomitopsis pinicola (130.2 mg/g) and Trametes versicolor (109.5 mg/g). P. chrysosporium contained 84.5 mg Cd /g dry weight.     

Native fungal pellets as a biosorbent for heavy metals

Abstract: Fungal pellets (diameters ranging from 0.5 to 2 mm) were precultured in sugar-containing industrial sewage. They were packed into chromatography columns and then tested for biosorption of silver, copper and lead, using the downflow method. The physical parameters taken (differential pressure at the column, flow rate, bed height) showed rather good mechanical properties of the pellets. Charging the column with heavy metal solution (1 mM Ag+, Cu2+ or Pb2+ as nitrates in distilled water) resulted in very good biosorptive properties. Eluted solution contained less than or an equal amount of 1 gM heavy metal, demonstrating a removal of more than 99.9% of added metal.     

Ion exchange/complexation of the uranyl ion by Rhizopus biosorbent

Nonliving biomass of nine Rhizopus species effectively sequestered the uranyl ion from solution, taking up 150-250 mg U/g dry cells at 300 ppm U equilibrium concentration in solution, and 100-160 mg U/g dry cells with 100 ppm U in solution. The affinity of this biosorbent for the uranyl ion was found to be affected by timing of harvesting and medium composition. Uptake of the uranyl ion by nonliving biomass of Rhizopus oligosporus was due to ion exchange or complexation, since binding was reversed by the addition of complexing ligands or the reduction of pH to a value less than 2. Uptake isotherms were interpreted in terms of a model of multiple equilibria. At pH 相似文献   

Biosorption of dyes using dead macro fungi: effect of dye structure, ionic strength and pH

Biosorbents prepared from dead macro fungi, namely Fomes fomentarius and Phellinus igniarius, were applied for the uptake of Methylene Blue (MB) and Rhodamine B (RB). Equilibrium isotherm data could be well described by the Langmuir and Freundlich models. Methylene Blue was found to be more adsorbable than Rhodamine B. Langmuir monolayer coverage was determined as 204.38-232.73 mg/g and 25.12-36.82 mg/g for MB and RB, respectively. Molecular structure and ionic radius of dyes were found to be responsible for differences in their uptakes. Results showed that sorption of MB increased while that of RB decreased as pH of respective dye solutions changed from 3 to 11. An increase in ionic strength also exhibited an adverse effect on dye sorption capacity. Ionic strength and pH affected the sorption of MB more as compared to the sorption of RB. The presence of carboxylic (-ve) and amino (+ve) groups in RB could explain the lower sorption of RB compared to MB.     

A simple method of isolation and purification of cultures of wood-rotting fungi

A simple method of isolation and purification of cultures of higher fungi, mainly wood-rotting fungi, without special requirements for the presence of nitrogencontaining nutrients is described. Parts of fruiting bodies, spores or infected wood is inoculated on Petri dishes with an agar medium of the following composition: 1.0 g KH2PO4, 0.2 g MgSO4 - 7 H2O, 0.1 g caSO4, 0.01 g Fe2(SO4)3, 10.0 g glucose, tap water to 1 litre; 20.0 g agar. This medium does not suit most of the contaminants but fungal hyphae overgrow the whole surface of the dish so that a purified culture can be obtained from parts distant from the inoculation site.     

Comparison of different types of biomasses for copper biosorption

Three biomass, birch wood Betula sp., marine brown alga Fucus vesiculosus, and terrestrial moss Pleurozium schreberi, have been compared as raw materials for preparation of biosorbents for removal of copper ions from diluted water solutions. Small sample doses (0.5 g/100ml) of the biosorbents prepared from alga and moss enabled more than 90% removal of Cu(II) ions from diluted water solutions (5-20mg/l). The sample from sawdust was less effective. A pseudo-second-order rate model properly described the experimental kinetic data for the biosorbents. The maximum sorption capacities (Xm) determined from the experimental equilibrium isotherms by applying the Langmuir model showed that the alga had the best copper-binding ability (Xm=23.4 mg/g), followed by the moss (Xm=11.1mg/g), and the sawdust (Xm=4.9 mg/g). No visible damages or performance losses were detected for the alga and moss after five sorption-desorption cycles using diluted HCl as eluent.     

Sorption of lead, cadmium, and zinc on sulfur-containing chemically modified wastes of fluted pumpkin (Telfairia occidentalis Hook f.)

We have tested the applicability of regular as well as sulfanylacetic acid (SA) modified fluted pumpkin waste biomass as adsorbents for Pb2+, Cd2+, and Zn2+ aqueous solutions by means of the batch-sorption technique. The data revealed that SA modification produces a larger surface area, enhancing the metal-ion binding capacity of the biomass. The sorption process was examined by means of Freundlich and Langmuir models. The kinetic study showed that the sorption rates can be described by a pseudo-second-order process. The rate constants for the control biomass (CB) were 2.2x10(-2), 4.4x10(-2), and 1.6x10(-2) mg g(-1) min(-1) for Pb2+, Cd2+, and Zn2+, respectively; and the corresponding rate constants for the SA-modified biomass were 4.0x10(-2), 4.7x10(-2), and 1.7x10(-2) mg g(-1) min(-1), respectively. Thermodynamic considerations indicated a spontaneous exothermic process, which implies that physisorption is the main mechanism in the sorption process.     

Distribution of acetyl esterase in wood-rotting fungi

The distribution of acetyl esterase was studied in 30 strains of wood-rotting fungi. A screening test on agar plates using glucose β-d-pentaacetate as a substrate indicated that all tested fungi produced acetyl esterase to form a clear zone on the culture. All fungi also showed positive responses in an agar test using carboxymethyl cellulose acetate. Enzyme assay showed that extracellular acetylxylan esterase activity was present in the filtrates of wood-meal culture of all these fungi. The ratio of fungal acetylxylan esterase activity to 4-nitrophenyl acetyl esterase activity were higher than that of porcine liver esterase, indicating that fungal esterases have high affinity for acetylated carbohydrates. Acetyl esterase is suggested to be distributed widely in wood-rotting fungi for degradation of native acetylated hemicelluloses.     

Suppression of the Root-knot Nematode Meloidogyne javanica by Alginate Pellets Containing the Nematophagous Fungi Hirsutella rhossiliensis , Monacrosporium cionopagum and M. ellipsosporum

The endoparasitic fungus Hirsutella rhossiliensis and the nematode-trapping fungi Monacrosporium cionopagum and M. ellipsosporum were formulated as hyphae in alginate pellets. In a soil microcosm experiment, dried pellets of all three fungi decreased the invasion of cabbage seedlings by the root-knot nematode Meloidogyne javanica when juvenile nematodes were placed 2 cm from roots; M. cionopagum was more effective than the other two fungi, reducing nematode invasion by 40-95% with 0.24-0.94 pellets cm - 3 of soil. In a field microplot experiment, in which neither H. rhossiliensis nor M. ellipsosporum suppressed nematodes, 0.5 pellets of M. cionopagum cm - 3 of soil suppressed M. javanica invasion of tomato seedlings by 73%. In a second microplot experiment with only M. cionopagum , again at 0.5 pellets cm - 3 of soil, the fungus suppressed the invasion of tomato seedlings whether the pellets were added 0, 5 or 14 days before planting; the population density of M. cionopagum increased to nearly 3000 propagules g - 1 of soil by day 8 and then declined to less than 300 by day 22. Enchytraeid worms were observed in and around damaged and apparently destroyed pellets in both microplot experiments. Whether enchytraeids consumed the fungi or otherwise affected biological control requires additional research.     

The efficiency of the red alga Mastocarpus stellatus for remediation of cadmium pollution

This work reports the results of the study for cadmium binding by the dead red macroalga Mastocarpus stellatus. Kinetics sorption experiments demonstrated the high rate of metal biosorption: the system attained over 50% of the total biomass cadmium uptake within 2 min of contact and over 90% in the first 9 min. The kinetic data were successfully described by a pseudo-second order model with rate constants ranging from 1.06 to 10 gmmol(-1)min(-1), as a function of initial metal concentration and temperature. The equilibrium binding was accurately represented in terms of Langmuir and Langmuir-Freundlich models. The sorption isotherms at constant pH showed uptake values as 0.49 mmol g(-1) (at pH 2.4), 0.56 mmol g(-1) (at pH 4) and 0.59 mmol g(-1) (at pH 6), while the affinity constant values were between 0.6 and 5 mmol(-1) L (Langmuir fit). The acid-base properties of the alga were also studied, obtaining the total number of acid groups, 2.5 mmol g(-1), and their apparent pK value, 1.56, using the Katchalsky model. Desorption studies were conducted employing different HNO(3) concentrations and desorption times.     

Biosurfactant Mediated Remediation Process Evaluation on a Mixture of Heavy Metal Spiked Topsoil Using Soil Column and Batch Washing Methods

This study investigated the effects of biosurfactant produced by a mangrove isolate on a heavy metal spiked soil remediation using two different methods of biosurfactant addition (pretreatment and direct application) at different concentrations (0.5%–5%) for 10 days employing column and batch method of washings. The FT-IR spectral and biochemical analysis confirmed the chemical nature of biosurfactant as a glycolipid. Pre-addition of biosurfactant at 0.5% concentrations and further incubation for a month resulted in better chromium removal than the direct biosurfactant washing method. A maximum recovery of lead (99.77%), nickel (98.23%), copper (99.62%), and cadmium (99.71%) were achieved with column washing method at 1% biosurfactant concentration. Release of 26% soluble fractions of nickel (pre-addition with biosurfactant) and 40% copper (direct application) were achieved by column washing method at 1.0% concentration of biosurfactant. A total of 0.034 mg/10 g of lead, 0.157 mg/10 g of nickel, 0.022 mg/10 g of copper, 0.025 mg/10 g of cadmium, and 0.538 mg/10 g of chromium were found to remain in the spiked soil after column washing with 1.0% biosurfactant solution. However, pre-addition of 0.5% biosurfactant treatment helps in maximum removal of chromium metal leaving a residual concentration of 0.426 mg/10 g of soil, suggesting effective removal at very low concentration. The average extraction concentration of metals in batch washings was between 93–100%, irrespective of the concentration of biosurfactant studied. In this study, the percentage removal of copper, cadmium, chromium, nickel, and lead from spiked soils by column washing was comparatively lower than batch washing.     

木材腐朽菌培养特性的研究综述

论述了研究木材腐朽菌培养特性的意义,对自1889年以来有关木材腐朽菌培养特性的研究文献进行了回顾。通过综合分析以往国内外对木材腐朽菌培养特性研究的结果,得出了对木材腐朽菌培养特性研究的总体结论。     

Biosorption of simulated dyed effluents by inactivated fungal biomasses

Treatment of dyed effluents presents several problems mainly due to the toxicity and recalcitrance of dyestuffs. Innovative technologies, such as biosorption, are needed as alternatives to conventional methods to find inexpensive ways of removing dyes from large volumes of effluents. Inactivated biomasses do not require a continuous supply of nutrients and are not sensitive to the toxicity of dyes or toxic wastes. They can also be regenerated and reused in many cycles and are both safe and environment-friendly. The sorption capacities (SC) of autoclaved biomasses of three Mucorales fungi (Cunninghamella elegans, Rhizomucor pusillus and Rhizopus stolonifer), cultured on two different media, were evaluated against simulated effluents containing concentrations of 1000 and 5000 ppm of a single dye and a mix of 10 industrial textile dyes in batch experiments. SC values of up to 532.8 mg of dye g(-1) dry weight of biomass were coupled with high effluent decolourisation percentages (up to 100%). These biomasses may thus prove to be extremely powerful candidates for dye biosorption from industrial wastewaters. Even better results were obtained when a column system with the immobilised and inactivated biomass of one fungus was employed.     

Thermodynamic and breakthrough column studies for the selective sorption of chromium from industrial effluent on activated eucalyptus bark

Studies were carried out on adsorption of Cr(VI) on an adsorbent made from eucalyptus bark. Results revealed that sorption of chromium on activated eucalyptus bark (AEB) was endothermic in nature. Thermodynamic parameters such as the entropy change, enthalpy change and Gibb's free energy change were found out to be 100.97 J mol(-1)K(-1), 33 kJ mol(-1) and -0.737 kJ mol(-1), respectively. Industrial chrome effluent of different chromium concentration at different pH was used as feedstock for the fixed bed adsorption studies. When effluent was fed to the column at low pH of 2, the breakthrough volume increased significantly compared to effluent at higher pH of 4.85. The surface properties of sorbent were characterized by the Scanning electron microscopy, X-ray diffraction technique and Infrared techniques. It was concluded that AEB sorbent column could be used effectively for removal of chromium from industrial effluents by reducing the pH of chrome effluent to two and at optimal column conditions.     

铜藻岩藻黄素提取及纯化工艺研究

为了对岩藻黄素的提取、纯化进行系统研究,进而为高纯度岩藻黄素的工业化生产提供研究基础,筛选了适用于提取铜藻（Sargassum horneri）鲜藻中岩藻黄素的有机溶剂,并通过单因素实验和正交实验确定了最佳的提取溶剂浓度、提取温度、提取时间、料液比等工艺参数。随后采用硅胶柱层析法进行纯化,并通过单因素实验确定了最佳的硅胶柱床高度、上样量和洗脱流速。最后采用制备液相法对经层析纯化的岩藻黄素进一步纯化。结果表明,有机溶剂萃取的最佳工艺条件为：甲醇浓度90%,提取温度50 ℃,提取时间1 h,料液比1∶10,此条件下岩藻黄素提取率达到(0.258 9±0.003 6) mg·g-1鲜重（FW）［(1.078 8±0.015 0) mg·g-1干重（DW）］。硅胶柱层析的最佳工艺条件为：硅胶柱床高度10 cm,上样量6 g,洗脱流速10 mL·min-1,此条件下岩藻黄素得率为0.176 5 mg·g-1FW（0.735 3 mg·g-1 DW）,纯度为87.01%±0.88%。经制备液相进一步纯化后,岩藻黄素得率为0.127 1 mg·g-1 FW（0.529 4 mg·g-1 DW）,纯度为99.27%±0.22%。研究所用工艺简单,岩藻黄素得率高,为高纯度岩藻黄素的制备提供了实验基础。     

Sorption of Cr(VI), Cu(II) and Pb(II) by growing and non-growing cells of a bacterial consortium

This paper reports the sorption of three metallic ions, namely Cr(VI), Cu(II) and Pb(II) in aqueous solution by a consortium culture (CC) comprising an acclimatised mixed bacterial culture collected from point and non-point sources. Metal sorption capability of growing and non-growing cells at initial pH of between 3 and 8 in the 1-100mg/L concentration range were studied based on Q(max) and K(f) values of the Langmuir and linearised Freundlich isotherm models, respectively. Maximal metal loading was generally observed to be dependent on the initial pH. Growing cells displayed significant maximal loading (Q(max)) for Pb(II) (238.09 mg/g) and Cu(II) (178.87 mg/g) at pH 6 and at pH 7 for Cr(VI) (90.91 mg/g) compared to non-growing cells (p < 0.05). At the pH range of 6-8, growing cells showed higher loading capacity compared to non-growing cells i.e. 38-52% for Cr, 17-28% for Cu and 3-17% for Pb. At lower metal concentrations and at more acidic pH (3-4) however, non-growing cells had higher metal loading capacity than growing cells. The metal sorption capacity for both populations were as follows: Pb(II) > Cu(II) > Cr(VI).     

Biosorption of heavy metals by Fucus spiralis

The sorption uptake of cadmium, nickel, zinc, copper and lead by marine brown alga Fucus spiralis was investigated in bimetallic, trimetallic and multimetallic solutions. The experimental data fitted very well to Langmuir model. In bimetallic systems, the affinity of biomass for lead and copper increased and the sorption uptake of these metals was not affected by increasing concentrations of cadmium, nickel or zinc. However, in solutions with both metals there was a significant mutual decrease of their sorption levels at high concentrations of the other metal. The sorption uptake of cadmium, nickel and copper was investigated in trimetallic aqueous systems. Based on the kinetic parameter b, the affinity of F. spiralis for copper was considerably higher than for cadmium or nickel: bCd=6.39, bNi=1.82 and bCu=17.89. In all tests, the maximum sorption uptake remained practically constant around 1 mmol/g, indicating that the number of active sites on the biomass was limited. Tests with four and five metals showed that copper was preferentially adsorbed. The differences between the experimental sorption data and those given by the chemical speciation program PHREEQCI were negligible. In general, the software used provided satisfactory estimated data for each metal and hence can be a useful tool to predict or simulate the real process.     

A comparative study on the production of exopolysaccharides between two entomopathogenic fungi Cordyceps militaris and Cordyceps sinensis in submerged mycelial cultures

AIMS: The present study comparatively investigates the optimal culture conditions for the production of exopolysaccharides (EPS) and cordycepin during submerged mycelial culture of two entomopathogenic fungi Cordyceps militaris and Cordyceps sinensis. METHODS AND RESULTS: Fermentations were performed in flasks and in 5-l stirred-tank fermenters. In the case of C. militaris, the highest mycelial biomass (22.9 g l(-1)) and EPS production (5 g l(-1)) were achieved in a medium of 40 g l(-1) sucrose, 5 g l(-1) corn steep powder at 30 degrees C, and an initial pH 8.0. The optimum culture conditions for C. sinensis was shown to be (in g l(-1)) 20 sucrose, 25 corn steep powder, 0.78 CaCl2, 1.73 MgSO4.7H2O at 20 degrees C, and an initial pH 4.0, where the maximum mycelial biomass and EPS were 20.9 and 4.1 g l(-1) respectively. Cordycepin, another bioactive metabolite, was excreted at low levels during the early fermentation period (maximum 38.8 mg l(-1) in C. militaris; 18.2 mg l(-1) in C. sinensis). CONCLUSIONS: The two fungi showed different nutritional and environmental requirements in their submerged cultures. Overall, the concentrations of mycelial biomass, EPS and cordycepin achieved in submerged culture of C. militaris were higher than those of C. sinensis. SIGNIFICANCE AND IMPACT OF THE STUDY: C. militaris and C. sinensis are representative insect-born fungi which have been longstanding and widely used as traditional medicines in eastern Asia. Comparative studies between two fungi are currently not available and this is the first report on the optimum medium composition for submerged culture of C. sinensis.     

Isolation and characterization of chitinolytic Streptomyces sp. MT7 and its antagonism towards wood-rotting fungi

An actinomycetes isolate of Loktak Lake soil, designated as MT7, was characterized and identified as Streptomyces sp. based on fatty acid methyl ester and 16S ribosomal RNA gene analysis. Streptomyces sp. MT7 showed strong and broad spectrum antagonism towards seven out of eight tested wood-rotting fungi. Strain MT7 secretes three vital fungal cell wall lytic enzymes, i.e. chitinase, β-1,3-glucanase, and protease, and siderophores. Extracellularly produced mycolytic enzymes lost their antifungal activity completely after treatment with proteinase K and heat, indicating that the tested antifungal metabolites are heat-sensitive and proteinaceous in nature. Extracellular fluid (ECF) and its organic solvent extract also exhibited potential antagonism towards the tested wood-rotting fungi. Antifungal metabolites were characterized as polyene in nature. Biocontrol traits like co-production of cell wall lytic enzymes and antifungal secondary metabolites including siderophores by Streptomyces sp. MT7 suggests that it could be employed as a potential biocontrol agent against wood-rotting basidiomycetes.